MySql GIS 空间数据库使用体验
本文时对MySql GIS中的部分函数做测试，便于理解和使用
1.理解下MySql GIS空间数据字段类型
1.一个点：POINT（15 20）
请注意，点坐标无指定分隔逗号。
2.一根线条，例如有四点组成的线条： LINESTRING（0 0，10 10，20 25，50 60）
请注意，点坐标对用逗号分隔。
3.一个多边形，例如一个外环和一个内环组成的多边形：POLYGON（（0 0,10 0,10 10 10 0 0），（5 5 7 5 7 7 5 7 5 5））
4.多点集合，例如三个点的值：MultIPOINT（0 0，20 20，60 60）
5.多线集合，例如两根线条的集合：MULTILINESTRING（（10 10，20 20），（15 15，30 15））
6.多边形集合，例如两个多边形值的集合：MULTIPOLYGON（（（0 0,10 0,10 10 10,0 0）），（（5 5 7 5 7 7 5 7 5 5）））
7.集合，例如两个点和一条线段的集合：GeometryCollection（POINT（10 10），POINT（30 30），LINESTRING（15 15，20 20））
2.添加测试数据
表t_pot 存储点信息，t_polygon存储几何信息
t_pot 创建语句（由于这里使用的是mysql 5.7的数据库，所以用InnoDB数据引擎，较低版本的数据库需要采用MyISAM ）
CREATE TABLE `t_pot` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`pot` point DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;
往t_pot表中添加测试数据
INSERT INTO `t_pot` VALUES ('1', 'A', GeomFromText('POINT(0 0)'));
INSERT INTO `t_pot` VALUES ('2', 'B', GeomFromText('POINT(0 2)'));
INSERT INTO `t_pot` VALUES ('3', 'C', GeomFromText('POINT(2 0)'));
INSERT INTO `t_pot` VALUES ('4', 'D', GeomFromText('POINT(2 2)'));t_polygon创建语句
CREATE TABLE `t_polygon` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`pgn` polygon DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8;往t_polygon表中添加测试数据
INSERT INTO `t_polygon` VALUES ('1', 'ABCD', GeomFromText('POLYGON((0 0, 2 0, 2 2, 0 2, 0 0))'));
INSERT INTO `t_polygon` VALUES ('2', 'AEGF', GeomFromText('POLYGON((0 0, 4 0, 4 4, 0 4, 0 0))'));
INSERT INTO `t_polygon` VALUES ('3', 'CEGFBD', GeomFromText('POLYGON((0 2, 0 4, 4 4, 4 0, 2 0, 2 2, 0 2))'));
INSERT INTO `t_polygon` VALUES ('4', 'AHJIK', GeomFromText('POLYGON((0 0, 0 6, 6 6, 6 0, 0 0), (2 2, 4 4, 4 2, 2 2))'));
INSERT INTO `t_polygon` VALUES ('5', 'DGK', GeomFromText('POLYGON((2 2, 4 4, 4 2, 2 2))'));
INSERT INTO `t_polygon` VALUES ('6', 'GKJ', GeomFromText('POLYGON((4 4, 4 2, 6 6, 4 4))'));
INSERT INTO `t_polygon` VALUES ('7', 'ADF', GeomFromText('POLYGON((0 0, 2 2, 4 0, 0 0))'));
INSERT INTO `t_polygon` VALUES ('8', 'LDK', GeomFromText('POLYGON((1 1, 2 2, 4 2, 1 1))'));t_pot表中的点坐标数据没有什么好解释的，下面对t_polygon数据进行说明
下面是表中对应的坐标点位置：
ABDC：POLYGON((0 0, 2 0, 2 2, 0 2, 0 0)) 面积为4的正方形
AEGF：POLYGON((0 0, 4 0, 4 4, 0 4, 0 0)) 面积为16的正方形
CEGFBD：POLYGON((0 2, 0 4, 4 4, 4 0, 2 0, 2 2, 0 2)) 面积为16的正方形 - 面积为4的正方形
DGK：POLYGON((2 2, 4 4, 4 2, 2 2))面积为2的直角等腰三角形
AHJIK：POLYGON((0 0, 0 6, 6 6, 6 0, 0 0), (2 2, 4 4, 4 2, 2 2)) 面积为36的正方形 - 面积为2的三角形DGK
GKJ ：POLYGON((4 4, 4 2, 6 6, 4 4)) 面积为2的三角形
ADF ：POLYGON((0 0, 2 2, 4 0, 0 0))面积为4的等腰三角形
LDK：POLYGON((1 1, 2 2, 4 2, 1 1))面积为1的三角形
3.测试SQL语句
ST_GEOMFROMTEXT文本数据转成空间数据，所以下面看着就乱码了(Navicate中是不乱码)
mysql> SELECT ST_GEOMFROMTEXT("POINT(1 2)");
+-------------------------------+
| ST_GEOMFROMTEXT("POINT(1 2)") |
+-------------------------------+
| ð? @ |
+-------------------------------+
1 row in set (0.00 sec)ST_ASTEXT空间数据转文本数据
mysql> SELECT ST_ASTEXT(ST_GEOMFROMTEXT("POINT(1 2)"));
+------------------------------------------+
| ST_ASTEXT(ST_GEOMFROMTEXT("POINT(1 2)")) |
+------------------------------------------+
| POINT(1 2) |
+------------------------------------------+
1 row in set (0.00 sec)st_distance两点之间直线距离
mysql> select st_distance(ST_GEOMFROMTEXT("POINT(0 0)"),p.pot),p.`name` from t_pot p;
+--------------------------------------------------+------+
| st_distance(ST_GEOMFROMTEXT("POINT(0 0)"),p.pot) | name |
+--------------------------------------------------+------+
| 0 | A |
| 2 | B |
| 2 | C |
| 2.8284271247461903 | D |
+--------------------------------------------------+------+
4 rows in set (0.00 sec)st_distance_sphere两点之间地理距离，单位米，例如记录店铺与用户间的距离
mysql> select st_distance(ST_GEOMFROMTEXT("POINT(0 0)"),p.pot),p.`name` from t_pot p;
+--------------------------------------------------+------+
| st_distance(ST_GEOMFROMTEXT("POINT(0 0)"),p.pot) | name |
+--------------------------------------------------+------+
| 0 | A |
| 2 | B |
| 2 | C |
| 2.8284271247461903 | D |
+--------------------------------------------------+------+
4 rows in set (0.00 sec)ST_Intersects图形是否有交叉重叠
mysql> SELECT
-> ST_Intersects(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,2 0,2 2,0 2,0 0))")),tp.`name`
-> FROM `t_polygon` tp;
+-------------------------------------------------------------------------+--------+
| ST_Intersects(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,2 0,2 2,0 2,0 0))")) | name |
+-------------------------------------------------------------------------+--------+
| 1 | ABCD |
| 1 | AEGF |
| 1 | CEGFBD |
| 1 | AHJIK |
| 1 | DGK |
| 0 | GKJ |
| 1 | ADF |
| 1 | LDK |
+-------------------------------------------------------------------------+--------+
8 rows in set (0.00 sec)ST_Equals图形是否有相等
mysql> SELECT
-> ST_Equals(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,2 0,2 2,0 2,0 0))")),tp.`name`
-> FROM `t_polygon` tp;
+---------------------------------------------------------------------+--------+
| ST_Equals(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,2 0,2 2,0 2,0 0))")) | name |
+---------------------------------------------------------------------+--------+
| 1 | ABCD |
| 0 | AEGF |
| 0 | CEGFBD |
| 0 | AHJIK |
| 0 | DGK |
| 0 | GKJ |
| 0 | ADF |
| 0 | LDK |
+---------------------------------------------------------------------+--------+
8 rows in set (0.00 sec)ST_Touches相接触，但不包含
mysql> SELECT
-> ST_Touches(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,2 0,2 2,0 2,0 0))")),tp.`name`
-> FROM `t_polygon` tp;
+----------------------------------------------------------------------+--------+
| ST_Touches(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,2 0,2 2,0 2,0 0))")) | name |
+----------------------------------------------------------------------+--------+
| 0 | ABCD |
| 0 | AEGF |
| 1 | CEGFBD |
| 0 | AHJIK |
| 1 | DGK |
| 0 | GKJ |
| 0 | ADF |
| 0 | LDK |
+----------------------------------------------------------------------+--------+
8 rows in set (0.00 sec)ST_Contains包含
mysql> SELECT
-> ST_Contains(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,2 0,2 2,0 2,0 0))")),tp.`name`
-> FROM `t_polygon` tp;
+-----------------------------------------------------------------------+--------+
| ST_Contains(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,2 0,2 2,0 2,0 0))")) | name |
+-----------------------------------------------------------------------+--------+
| 1 | ABCD |
| 1 | AEGF |
| 0 | CEGFBD |
| 1 | AHJIK |
| 0 | DGK |
| 0 | GKJ |
| 0 | ADF |
| 0 | LDK |
+-----------------------------------------------------------------------+--------+
8 rows in set (0.00 sec)ST_SymDifference返回表示设置的几何值的对称差的点的几何形状 g1和 g2，这语话加了ST_ASTEXT，把空间数据转换成文本，要不然看着乱码的(Navicate中是不乱码)
mysql> SELECT
-> ST_ASTEXT(ST_SymDifference(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,4 0,4 4,0 4,0 0))"))),tp.`name`
-> FROM `t_polygon` tp;
+---------------------------------------------------------------------------------------+--------+
| ST_ASTEXT(ST_SymDifference(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,4 0,4 4,0 4,0 0))"))) | name |
+---------------------------------------------------------------------------------------+--------+
| POLYGON((0 2,2 2,2 0,4 0,4 4,0 4,0 2)) | ABCD |
| GEOMETRYCOLLECTION() | AEGF |
| POLYGON((0 2,0 0,2 0,2 2,0 2)) | CEGFBD |
| POLYGON((4 2,4 0,6 0,6 6,0 6,0 4,4 4,2 2,4 2)) | AHJIK |
| POLYGON((4 4,0 4,0 0,4 0,4 2,2 2,4 4)) | DGK |
| POLYGON((4 4,0 4,0 0,4 0,4 2,6 6,4 4)) | GKJ |
| POLYGON((4 0,4 4,0 4,0 0,2 2,4 0)) | ADF |
| POLYGON((4 2,4 4,0 4,0 0,4 0,4 2),(4 2,1 1,2 2,4 2)) | LDK |
+---------------------------------------------------------------------------------------+--------+
8 rows in set (0.00 sec)ST_Intersection在指定范围内交叉的集合
mysql> SELECT
-> ST_ASTEXT(ST_Intersection(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,2 0,2 2,0 2,0 0))"))),tp.`name`
-> FROM `t_polygon` tp;
+--------------------------------------------------------------------------------------+--------+
| ST_ASTEXT(ST_Intersection(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,2 0,2 2,0 2,0 0))"))) | name |
+--------------------------------------------------------------------------------------+--------+
| POLYGON((0 2,0 0,2 0,2 2,0 2)) | ABCD |
| POLYGON((0 2,0 0,2 0,2 2,0 2)) | AEGF |
| LINESTRING(0 2,2 2,2 0) | CEGFBD |
| POLYGON((0 2,0 0,2 0,2 2,0 2)) | AHJIK |
| POINT(2 2) | DGK |
| GEOMETRYCOLLECTION() | GKJ |
| POLYGON((2 2,0 0,2 0,2 2)) | ADF |
| POLYGON((2 2,1 1,2 1.3333333333333335,2 2)) | LDK |
+--------------------------------------------------------------------------------------+--------+
8 rows in set (0.00 sec)还是上面的语句，但是把范围调整了为了更清楚的分析数据
mysql> SELECT
-> ST_ASTEXT(ST_Intersection(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,4 0,4 4,0 4,0 0))"))),tp.`name`
-> FROM `t_polygon` tp;
+---------------------------------------------------------------------------------------+--------+
| ST_ASTEXT(ST_Intersection(tp.pgn,ST_GEOMFROMTEXT("POLYGON((0 0,4 0,4 4,0 4,0 0))"))) | name |
+---------------------------------------------------------------------------------------+--------+
| POLYGON((0 2,0 0,2 0,2 2,0 2)) | ABCD |
| POLYGON((0 4,0 0,4 0,4 4,0 4)) | AEGF |
| POLYGON((0 4,0 2,2 2,2 0,4 0,4 4,0 4)) | CEGFBD |
| GEOMETRYCOLLECTION(MULTIPOLYGON(((0 4,0 0,4 0,4 2,2 2,4 4,0 4))),LINESTRING(4 4,4 2)) | AHJIK |
| POLYGON((4 4,2 2,4 2,4 4)) | DGK |
| LINESTRING(4 4,4 2) | GKJ |
| POLYGON((4 0,2 2,0 0,4 0)) | ADF |
| POLYGON((4 2,2 2,1 1,4 2)) | LDK |
+---------------------------------------------------------------------------------------+--------+
8 rows in set (0.00 sec)mysql> select AREA(tp.pgn),tp.`name`
-> FROM `t_polygon` tp;
+--------------+--------+
| AREA(tp.pgn) | name |
+--------------+--------+
| 4 | ABCD |
| 16 | AEGF |
| 12 | CEGFBD |
| 34 | AHJIK |
| 2 | DGK |
| 2 | GKJ |
| 4 | ADF |
| 1 | LDK |
+--------------+--------+
8 rows in set, 1 warning (0.00 sec)还有更多的函数的使用和说明可以参考：mysql 函数说明